This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Magnetic Resonance Imaging (MRI) systems enable imaging based on a primary magnetic field, a radio frequency (RF) pulse, and time-varying magnetic gradient fields that interact with specific nuclear components in an object, such as hydrogen nuclei in water molecules. The magnetic moments of such nuclei may generally align with the primary magnetic field, but subsequently precess about the bulk magnetic field direction at a characteristic frequency known as the Larmor frequency. An RF pulse at or near the Larmor frequency of such nuclei may cause their magnetic moments to be rotated. When the RF pulse has ended, the magnetic moments relax and generally align with the primary magnetic field, emitting a detectable signal.
Some of the magnetic gradient fields in MRI are produced by a series of gradient coils. In particular, the gradient coils create magnetic fields of varying strength along various imaging planes to produce a gradient along each plane. Nuclei of interest (e.g., hydrogen) align their spins according to the gradients. This results in spatial encoding, where spatial information about the location of the excited hydrogen nuclei can be obtained during acquisitions. Strong amplifiers power the gradient coils, allowing them to rapidly and precisely adjust the magnetic field gradients.
Generally, gradient coils for conventional cylindrical whole body magnetic resonance imaging (MRI) systems are manufactured by laying machined or wound electrical conductor material that has been rolled into a cylindrical shape onto a cylindrical former. Planar and other non-right circular cylindrical geometries for the gradient coils are also used for MRI. The teachings in this application herein do not preclude its use in non-right circular cylindrical geometries and are in fact applicable to other geometries. Moreover, various other layers including spacers, dielectric insulators, cooling features, passive shim bars, resistive shim assemblies, and RF shield are laid onto the cylindrical former to complete a gradient coil assembly. The performance of the gradient coils is dependent, at least in part, on the precise alignment of the layers before being fixed or bound to the cylindrical former. In addition, the manner in which the gradient coils are formed may affect their durability. For example, the durability of the gradient coils may decrease due to stress resulting from winding or otherwise bending the coils to a desired shape. Furthermore, additional gradient coil features (e.g. soldering pads, connecting leads, jumpers and barbs) are brazed onto the MRI gradient boards, which can introduce weak points into the coil assembly. Unfortunately, many of the above processes may be performed by hand, which can introduce manufacturer error and uncertainty into the overall manufacturing process.